1. Field of the Invention
The invention relates to an automatic drive control system.
2. Description of the Related Art
Hitherto, there has been known an automatic drive control system for a vehicle such as an automobile, in which a train of lane markers such as magnetic nails or the like provided on the road surface is used as a reference line and signals which are generated from the lane markers are detected, thereby recognizing a relative position of the vehicle with respect to the reference line and automatically steering the vehicle so as to adjust the center line of the vehicle along the reference line.
As a prior art, for example, there is a system disclosed in Japanese Patent Kokai 9-62346. This system comprises: a navigation apparatus for detecting a position of a vehicle carrying the navigation apparatus by using not only signals which are generated because of the magnetic nails but also signals from the global positioning system (GPS); and a communicating apparatus which can receive various traffic information from beacons provided at every predetermined intervals on the sides of the road. In this system, a running line is set along the reference line in accordance with the running environment and the vehicle is steered along the set running line.
In order to detect a running on a rut formed on the road, the system has a yaw rate sensor and a lateral acceleration sensor and detects a forming state of the rut by a camera mounted thereon, thereby setting the running line suitable for the road on which the vehicle is running.
In this system, the running line for the reference line can be made unspecified by changing a positional relation between the reference line and the center of the vehicle with the elapse of the time, thereby to prevent the formation of the rut.
In the conventional automatic steering system, however, the reference line is recognized by detecting the signals produced because of the magnetic nails on the road, and the automatic steering is performed so as to trace a desired running line. When, for example, positions of the magnetic nails 2 which are arranged in a center portion of a lane 1 of a road do not exist on a smooth curve along a curvature of the lane, as shown in FIG. 1A, a running line 3 which is set by tracing the nails does not draw a smooth curve around the center of the lane. In other words, a vehicle 4 is so steered that a straight line 5 connecting two adjacent magnetic nails coincides with the vehicle center line. When, therefore, the steering is performed so as to trace the magnetic nails 2 which are not correctly arranged on the center of the road as shown in FIG. 1A, the running line 3 of the vehicle has a zigzag form.
When the setting interval of the magnetic nails in the longitudinal direction of the road is wide, the recognition of the nails as a reference line is not stabilized, so that the vehicle is likely out of a desired course.
As disclosed in Japanese Patent Kokai 9-62346, in the method of changing the position of the vehicle relative to the reference line with the elapse of time, there has been a problem such that a predetermined running line is missing, since the change width is limited to a detecting range of magnetic nail signal detecting means provided for the vehicle and the movement of the vehicle exceeding the signal detecting range is necessary or occurs for the reference line for the purpose of, for example, avoidance of an obstacle.
It is, therefore, an object of the invention to provide an automatic drive control system for a motor vehicle, which can perform an automatic steering in accordance with a driving situation of the motor vehicle without limiting to only a tracing operation of marks such as magnetic nails or the like provided on a road.
According to the invention, there is provided an automatic drive control system for a motor vehicle, comprising: radar means for detecting an existence of an obstacle in front of a vehicle so as to produce an obstacle detection signal; photographing means for photographing a road surface in front of the vehicle so as to produce a video signal; image processing means for generating a vehicle position signal indicative of a position of the vehicle in the width direction of the road from an image represented by the video signal; a navigation apparatus for generating road data indicative of coordinates of the road in front of the current position of the vehicle; communicating means for receiving a traffic information signal for automatic driving; running command generating means for generating a running command; running course setting means for setting a running course on the basis of the running command, obstacle detection signal, vehicle position signal, road data, and traffic information signal for automatic driving; and target running locus calculating means for obtaining a target running locus on the basis of the set running course, wherein the vehicle is steered so as to trace the target running locus.
Since the vehicle sets the running course on the road where it is running, it is unnecessary to provide the lane markers such as magnetic nails or the like on the road surface and detecting the signals from the lane markers even for the automatic staring for the motor vehicle. Even in the running state of the vehicle such as lane change, branching, or junction in which the detection of the lane markers is interrupted (discontinued), smooth steering for the vehicle can be maintained.